The answer is "A". As benefitial means good or well
logos is using logic so it could be that, and ethos is using a character or tries to convince you of its credibility so that is another option. Decide if their trying to appeal to credibility or if the statistic is more important.
The answer is C. a stone monument
To use your example, cede does mean to go. However, "recede" means to draw back or go back. Think of an ocean. What does the tide do at certain times? It recedes!
So re- is the best answer.
